1. Field of the Invention.
The present invention relates to a reference current generator and, more particularly, to a reference current generator with gated-diodes.
2. Description of the Related Art.
An ideal reference current generator is a circuit which outputs a current that remains constant over variations in temperature. In actual practice, however, reference current generators typically output currents that fall within a narrow range of values over a range of temperatures.
FIG. 1 shows a schematic diagram that illustrates a conventional current generator 100. As shown in FIG. 1, generator 100, which is commonly referred to as a current mirror, includes a diode-connected p-channel transistor 110 which is connected to a power supply node VCC.
In addition, generator 100 also includes a diode-connected n-channel transistor 112 which is connected to transistor 110 and ground, and a mirror transistor 114 which is connected to transistor 112 and ground.
In operation, a current I.sub.1 is forced to flow through diode-connected transistors 110 and 112.
Current I.sub.1. in turn, sets up the gate-to-source voltage V.sub.GS for both transistors 112 and 114 which causes a reference current I.sub.REF to be sunk by transistor 114.
One of the disadvantages of generator 100, however, is that the magnitude of the reference current I.sub.REF typically has a large variation over changes in temperature. Thus, there is a need for a reference current generator which is insensitive to changes in temperature.